Drilldown: Medicines
Medicines > fda max 
:
Indication-specific; titrated to effect or
No fixed maximum; titrated to TSH target
:
Indication-specific; titrated to effect or
No fixed maximum; titrated to TSH target Use the filters below to narrow your results.
generic:
brand:
classes:
mechanism:
None (1) ·
Synthetic T4 (thyroxine); peripherally deiodinated to T3 (triiodothyronine), the active hormone. '"`UNIQ--vote-00000031-QINU`"' Narrow therapeutic index; brand-to-generic switches can shift TSH and require re-titration'"`UNIQ--ref-00000032-QINU`"'. (1) ·
'"`UNIQ--vote-00000016-QINU`"' Brand-to-brand and lot-to-lot variability in T3:T4 ratio is greater than with synthetic levothyroxine, which is why endocrine guidelines prefer the synthetic'"`UNIQ--ref-00000017-QINU`"'. (1)
uses:
'"`UNIQ--vote-00000018-QINU`"', '"`UNIQ--vote-00000019-QINU`"' (1) ·
'"`UNIQ--vote-00000033-QINU`"', '"`UNIQ--vote-00000034-QINU`"', '"`UNIQ--vote-00000035-QINU`"' (1) ·
'"`UNIQ--vote-00000C0A-QINU`"', '"`UNIQ--vote-00000C0B-QINU`"', '"`UNIQ--vote-00000C0C-QINU`"', '"`UNIQ--vote-00000C0D-QINU`"', '"`UNIQ--vote-00000C0E-QINU`"' (1)
starting dose:
1.6 mcg/kg/d in young healthy adults; 25-50 mcg/d in elderly or cardiac disease, titrated by TSH at 6-8 weeks (1) ·
30 mg PO daily (1/2 grain); titrate by TSH at 6-8 weeks; 60 mg desiccated thyroid is approximately equivalent to 88-100 mcg levothyroxine (1) ·
SL 0.3-0.6 mg every 5 minutes up to 3 doses for acute angina (call EMS if not resolved after the third); IV infusion 5-10 mcg/min titrated; transdermal patch 0.2-0.4 mg/hr for 12-14 hours daily (nitrate-free interval prevents tolerance) (1)
preparations:
15, 30, 60, 90, 120, 180, 240, 300 mg tablets (1/4 to 5 grains; 1 grain = 60 mg) (1) ·
25, 50, 75, 88, 100, 112, 125, 137, 150, 175, 200, 300 mcg tablets; oral capsule and IV/IM also available (1) ·
SL 0.3, 0.4, 0.6 mg tablets; lingual spray 0.4 mg/spray; ER 2.5-9 mg capsules; transdermal patch 0.1-0.8 mg/hr; 2% ointment; 0.4% rectal ointment; 5 mg/mL IV (1)
fda max: (Click arrow to add another value)
routes:
onset:
halflife:
bioavailability:
40-80% (oral); reduced by food, calcium, iron, PPIs, fiber; take fasting with water'"`UNIQ--ref-00000037-QINU`"' (1) ·
Highly route-dependent: SL bypasses first-pass; oral has extensive first-pass (used only for chronic ER preparations); transdermal predictable'"`UNIQ--ref-00000C10-QINU`"' (1) ·
Variable; reduced by food, calcium, iron, PPIs'"`UNIQ--ref-0000001B-QINU`"' (1)
pregnancy:
First-line in pregnancy; dose typically increased 25-30% due to estrogen-driven rise in TBG and fetal demand. Lactation safe at physiologic doses.<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1) ·
Synthetic levothyroxine is the standard-of-care in pregnancy; desiccated thyroid use in pregnancy is not well studied.'"`UNIQ--ref-0000001C-QINU`"' (1) ·
Used in obstetric emergencies (uterine relaxation, severe hypertension) when needed; otherwise limited routine use.<sup class="pcp-cn" title="This claim needs a citation.">[[[Pharmacopedia:Citation needed|citation needed]]]</sup> (1)
Showing below up to 3 results in range #1 to #3.